1. Field of the Invention
This invention relates to transparent film layers deposited on the surfaces of non-metallic substrates, such as glass, to a new electrode in an electrochromic device, to a new electrochromic device, and to a method of making a copper oxide electrochromic device.
2. Description Of The Related Art
Electrochromism is a coloring phenomenon observed in some materials when they are placed in the presence of an electrical field. Such materials are normally uncolored when no electrical field is present, but change to a colored state when an electrical field is placed around the materials.
A material exhibiting reversible color changes is known as an electrochromic material (ECM). The phenomenon of transition from an uncolored state to a colored state in response to the presence and absence of an electrical field is called optical switching. If a thin coating of an ECM is placed on a glass support, the entire device is known as a switchable window. When no electrical field is placed on the ECM of a switchable window, the ECM is uncolored and transparent and thus one can look through the window. On the other hand, when an electric field is placed on the ECM, it colors, thereby reducing the amount of light transmitted through the window. The reduction of light transmission may be partial or total, either reducing the amount of light which passes through the window or eliminating it altogether.
Certain transition metal oxides are known to exhibit electrochromism. Materials such as tungsten oxide, molybdenum oxide, and vanadium oxide are known electrochromic materials. U.S. Pat. No. 4,830,471, issued to Hulya Demiryont, discloses an ECM comprising uncolored copper oxide. At column 6, lines 43-60, this patent teaches that "uncolored copper oxide" as an ECM is defined by its inventor as a layer of copper oxide which is transparent after it is laid down. U.S. Pat. No. 4,830,471 dismisses from the category of ECM's copper oxide with a colorish cast to it: "[I]t will not work as a suitable electrochromic material". U.S. Pat. No. 4,830,471, column 6, lines 45-48.
A good electrochromic device includes five layers: a transparent electrode, a counter electrode, an ion conducting layer, an electrochromic film, and a transparent electrode. A purpose of a counter electrode is to balance the chemical reaction which occurs at the boundary layer of the electrochromic layer, to avoid disintegration of the ion conducting layer.
It is an object of this invention to provide a new electrochromic material.
It is a feature of this invention that a new electrochromic material is provided which may include colored copper oxide.
It is an advantage of this invention that a newly provided ECM having copper oxide can be readily made.
It is another object of this invention to provide an electrochromic device having a new ECM therein.
It is another feature of this invention that a electrochromic device can be constructed with a newly provided ECM having a layer of copper oxide and a layer of tungsten oxide.
It is another advantage of this invention that an electrochromic device can be constructed using a newly provided ECM having a layer of copper oxide and a layer of tungsten oxide provided by pyrolytic film deposition.
It is yet another object of this invention to provide a method of making a copper oxide electrochromic device by layering of colored copper oxide and tungsten oxide.
It is still another object of this invention to provide a new material for a counter electrode.